Digital Level

ABSTRACT

A tool, such as a digital level, having multiple methods of indicating the orientation of the level. One embodiment of the level includes two or more accelerometers arranged in complimenting orientations, such as 90 degrees with respect to each other. The complimenting orientation allows for more precise measurements from less expensive accelerometers compared to a level with a single more expensive accelerometer. A power supply module, and an associated control module in charge of the power supply, selectively provides power to the accelerometers and displays based in part on user input, movement of the level, and the disposition of the level.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation of International Application No.PCT/US2019/015110, titled “Digital Level,” filed Jan. 25, 2019, whichclaims priority from U.S. Application No. 62/622,011, titled “DigitalLevel,” filed Jan. 25, 2018, and U.S. Application No. 62/663,945, titled“Digital Level,” filed Apr. 27, 2018, and the contents of which areincorporated herein in their entireties.

BACKGROUND OF THE INVENTION

The present invention relates generally to the field of levels, and morespecifically to a digital level.

Levels are used for a variety of applications, particularly in thebuilding and construction trades. Traditionally, to measure orientationa level uses one or more vials that contain a liquid (e.g., ethanol) anda small bubble of gas (e.g., air). The walls of the vial arearcuate-shaped such that when the level is placed on a sufficientlyhorizontal or vertical surface, the bubble of air is aligned at or nearthe center of at least one of the vials.

SUMMARY OF THE INVENTION

In one embodiment, a level comprises a housing. The housing comprising alongitudinal axis, a planar base surface, a top surface opposing thebase surface, an orientation sensor, such as an accelerometer, acontroller and a display. The controller calculates an orientationdifference between the housing orientation and a target orientation. Thetarget orientation is one of a selected orientation and a default targetorientation (e.g., level with level ground, plumb to level ground).

The level comprises one or more displays, one of which is on a frontsurface of the housing and another is on a top surface of the housing.The display on the front surfaces emits a first image that rotates withrespect to the housing such that alphanumeric characters in the firstimage are orientated level with respect to level ground independent ofthe orientation of the level itself.

One embodiment of the invention relates to a digital level that includestwo accelerometers, a display and a power supply. The accelerometers aredisposed in a complimentary arrangement, such as a 90 degree rotationwith respect to each other. Thus, the resolution error for using thecombination of the two accelerometers is minimized for differentorientations. In some embodiments, the accelerometers generate inputsignals that are processed by a processor to determine an orientation ofthe level housing, which is then used to display the orientation to theuser.

In one embodiment, features on a circular display rotate so that thefeatures are perpendicular with respect to the downward pull of gravity,and thus generally horizontal with respect to level ground. For example,a number representing the orientation (e.g., angle) of the level, thebattery status of the level, a line indicating the orientation of thelevel, a line indicating the plumb line that is parallel to the downwardpull of gravity, and the target orientation may be continually rotatedaround the display so that they maintain the same orientation withrespect to level ground.

In another embodiment, the display of the level changes its backgroundcolor when the level is within an acceptable range of the target angle.For example, the background may be a first color or pattern (e.g.,green, a solid color, etc.) when the level is reading within the primaryacceptable range, a second color or pattern different from the firstcolor or pattern (e.g., yellow, a checked pattern, etc.) when the levelreading is outside the primary acceptable range but within the secondaryacceptable range, and/or a third color or pattern different from thefirst and second colors (e.g., red, flashing, etc.) when the levelreading is outside the secondary acceptable range.

In another embodiment, alternate angles (e.g., angles other than 0 or 90degrees) may be selected as the target orientation for the level. Forexample, a user may place the level on a surface that is oriented at anangle the user wants to duplicate. The target button is depressed whilethe level is at the desired orientation, and subsequently the levelidentifies that orientation as the target angle. Alternatively, a usermay manually enter or adjust a target angle via the one or more inputbuttons.

In one or more embodiments, the digital level includes a control modulethat reduces or minimizes the power draw on the power supply (e.g., thebatteries). For example, the control module may be configured to enter asleep mode in any of several situations, such as when the device has notreceived user input for a threshold period of time. The control modulemay also utilize a depleted operational mode when the battery supply isbelow a threshold amount of power. In the depleted operational mode thedisplay may be dimmer, one of the displays may be entirely turned off,and/or the level may enter sleep mode after a threshold period of timethat is shorter than during normal operations, etc.

In one embodiment, the level includes a coarse view mode and a detailedview mode. As the level housing's orientation approaches the targetorientation, the level (e.g., a controller) determines to switch thedisplay to a detailed view mode based on a comparison of the levelorientation to the target orientation. The transition point from thecoarse view mode to the detailed view mode is user-configurable, and mayhave a default value of 3 degrees in either direction from the targetorientation.

In the detailed view mode, the marks on the level's display thatcorrespond to the level's orientation exaggerate the angle of the level.For example, if the level's physical orientation is 3 degrees away fromthe target orientation, the level's displayed orientation is at a 30degree angle from the target orientation. As the level's physicalorientation approaches the target orientation, the level's displayedorientation correspondingly approaches the target orientation mark onthe display. In various embodiments changes to the level's physicalorientation linearly correspond to changes to the level's displayedorientation (e.g., when the level changes orientation 1 degree towardsthe target orientation, the displayed orientation changes 10 degreestowards the target orientation).

In various embodiments, the target orientation of the level can betoggled to its mirror-image. For example, if the target orientation isthe left-side of the level being 13 degrees higher than the right-sideof the level, the mirror-image target orientation is the right-side ofthe level being 13 degrees higher than the left-side of the level. Onemethod of toggling the target orientation to its mirror-image is todouble-tap an input button.

In various embodiments, the display lists several user-selectable targetorientations. The entries in the list can be changed depending on thecircumstances that the level is being used in.

In various embodiments, the level includes several power modes. In aSleep Mode, the display(s) of the level are disabled and the inputbuttons, except for the power button, are similarly disabled. If thelevel includes multiple processors, the processor that requires lessenergy to operate is used while in Sleep Mode.

The level may enter Sleep Mode for any of several reasons, including thelevel being immobile for a time period, the level being placed in apredetermined orientation (e.g., on its face with the front display onthe bottom).

The level also has a Depleted Mode that the level enters when thebattery power source for the level is below a predetermined level (e.g.,10%, 20%). In the Depleted Mode, the level may disable the display thatrequires more energy to operate (e.g., the front display).

Additional features and advantages will be set forth in the detaileddescription which follows, and, in part, will be readily apparent tothose skilled in the art from the description or recognized bypracticing the embodiments as described in the written descriptionincluded, as well as the appended drawings. It is to be understood thatboth the foregoing general description and the following detaileddescription are exemplary.

The accompanying drawings are included to provide further understandingand are incorporated in and constitute a part of this specification. Thedrawings illustrate one or more embodiments and, together with thedescription, serve to explain principles and operation of the variousembodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective front view of a level, according to an exemplaryembodiment.

FIG. 2 is a detailed front view of the sidewall display of the level ofFIG. 1, according to an exemplary embodiment.

FIG. 3 is a detailed front view of the sidewall display of the level ofFIG. 1, according to another exemplary embodiment.

FIG. 4 is a detailed and annotated front view of a portion of thesidewall display of the level of FIG. 1, according to an exemplaryembodiment.

FIG. 5 is a front view of a portion of the sidewall display of the levelof FIG. 1, according to an exemplary embodiment.

FIG. 6 is a demonstrative illustration of features in a level display,according to an exemplary embodiment.

FIG. 7 is a front view of a level display, according to an exemplaryembodiment.

FIG. 8 is a perspective front view of a level, according to an exemplaryembodiment.

FIG. 9 is a front view of a level, according to an exemplary embodiment.

FIG. 10 is a front view of a level, according to an exemplaryembodiment.

FIG. 11 is a front view of a level display, according to an exemplaryembodiment.

FIG. 12 is a front view of a level display, according to an exemplaryembodiment.

FIG. 13 is a front view of a level display, according to an exemplaryembodiment.

FIG. 14 is a front view of a level display, according to an exemplaryembodiment.

FIG. 15 is a front view of a level display, according to an exemplaryembodiment.

FIG. 16 is a block diagram of several modules of a control system of thelevel of FIG. 1, according to an exemplary embodiment

FIG. 17 is detailed front view of an input device of the level of FIG.1, according to an exemplary embodiment

FIG. 18 is a block diagram of an orientation sensor including twoaccelerometers in the level of FIG. 1, according to an exemplaryembodiment

FIG. 19 is a chart of error measurement estimates of accelerometers atthe orientations illustrated in FIG. 18, according to an exemplaryembodiment.

FIG. 20 is a perspective view of a level, according to an exemplaryembodiment.

DETAILED DESCRIPTION

Referring generally to the figures, various embodiments of a digitallevel are shown. Various embodiments of the digital level discussedherein include an orientation sensor that includes an accelerometerorientation/arrangement to measure the level housing's orientation andprovide increased accuracy in readings for angles frequently used (e.g.,housing orientations horizontal to the ground and perpendicular to theground). In particular, the orientation sensor includes a pair ofaccelerometers rotationally oriented relative to each other in a mannerthat improves orientation reading accuracy. Applicant believes that byusing a plurality of accelerometers positioned in a complimentaryfashion as discussed herein, more accurate position readings areprovided while allowing for use of lower quality, lower cost and/orlower accuracy accelerometers (as compared to a design that providesorientation reading via a single high quality/high accuracyaccelerometer).

In one embodiment, the level includes a coarse view mode and a detailedview mode. When the level's orientation gets sufficiently close to thetarget orientation, the display switches to a detailed view mode. In thedetailed view mode, the marks on the level's display that correspond tothe level's orientation exaggerate the angle of the level. For example,if the level's physical orientation is 3 degrees away from the targetorientation, the level's display indicates an orientation that is 30degrees from the target orientation.

In various embodiments, the level includes several power modes,including a Power Mode, a Sleep Mode, and a Depleted Mode. For each ofthese modes various components and/or features of the level may bedisabled or have a reduced functionality. One benefit of these modes isto save power for the level, which increases runtime of the level.

In one embodiment, level includes a level body housing defining at leastone reference surface that is configured to engage a workpiece. To savepower when not in use, the level controller selectively uses a sleepmode based on remaining battery power, user input, sensed movement,and/or level orientation. The level controller also selectively uses areduced functionality mode that limits and/or reduces power to somefeatures (e.g., allowing the display to emit bright light) in order tomaintain power for other features (e.g., power the orientation sensor).Applicant believes this innovative power usage approach will eliminatethe need for a bulky and expensive battery while still allowing thelevel to be powered for a sufficient duration.

Referring to FIGS. 1-3, a level, such as digital level 10, is shownaccording to an exemplary embodiment. In general, level 10 includeshousing 15, controller 12, first display 18, second display 40, andinput module 50. The level body includes a generally planar base surface8 and an opposing upper surface 8 that is generally parallel to theplanar base surface. As will be generally understood, the base of thelevel is placed on a workpiece (e.g., a structure, surface, etc.) inorder for the user of the level to measure the orientation of a surfaceof the workpiece, including but not limited to whether the surface islevel or plumb.

Level 10 includes first measuring surfaces 8 on a top and bottom oflevel 10 (from the perspective of FIG. 1), and second measuring surfaces6 on a front and back of level 10 (from the perspective of FIG. 1).Measuring surfaces of level 10 provide very flat surfaces that permitlevel 10 to measure the orientation of other objects by placing one ofthe measuring surfaces of level 10 against the object being measured. Itis considered that level 10 may have any number of measuring surfaces(e.g., 1-4). Level 10 also includes a longitudinal primary axis 4 thatis aligned with the length of level 10.

First display 18 is the primary output device and is arranged on anexterior sidewall of housing 15. First display 18 includes one or moreinstances of alphanumeric characters, such as target 24, whichrepresents the target orientation of level 10. Reading line 20 indicatesthe orientation difference between the current orientation of level 10and a perceived direction of the force of gravity according to signalsreceived from the accelerometers. For example, in FIG. 2 both targets 24are not aligned with reading line 20. In particular, the right-mosttarget 24 is below reading line 20, and the left-most target 24 is abovereading line 20. This indicates that level 10 is tilted such that theright-side of level 10 (from the perspective of FIG. 2) is too high, andthe left-side of level 10 is too low.

Plumb indicators 23 correspondingly are oriented 90 degrees with respectto target 24, so that while target 24 tracks the target orientation ofthe primary axis of level 10, plumb indicator 23 tracks the Normal withrespect to that target orientation (for example, when the targetorientation is horizontal with respect to the ground, such as for levelground, plumb indicator 23 is vertical with respect to the ground).

In the example in FIG. 2, the actual reading 28 of level's orientationis 3.89 degrees. In this example, this orientation is within theacceptable range of readings, which is represented by acceptable margin26. In one or more embodiments, acceptable margin 26 is a fixed numberof degrees different than the target (e.g., 6 degrees in eitherdirection, 0.3 degrees in either direction), although a user mayconfigure level 10 to have a user-customized acceptable margin 26. Inone or more embodiments discussed herein the orientation of levelgenerally refers to the orientation of the level's housing.

As level 10 is rotated perpendicularly to its primary axis by tiltingeither end up or down, both targets 24 correspondingly rotate withinfirst display 18. For example, if the right-side of level 10, as seen inFIG. 2, is moved upward, then the right-most target 24 and theright-most acceptable margins 26 will correspondingly rotatecounter-clockwise around periphery 34 of display 18. Thus, even thoughdisplay 18 is not physically rotating, elements 78 in image 76 withindisplay 18 are rotating in concert with the rotation of level 10. It iscontemplated that all or part of image 76 may rotate with respect tohousing 15. In one or more embodiments image 76 comprises multipleimages 76, at least one of which rotates with respect to the housing andat least one of which does not rotate with respect to the housing (e.g.,a first image 76 rotates with respect to housing 15 so that the firstimage 76 is level with the ground independent of the orientation ofhousing, and a second image 76 does not rotate with respect to thehousing 15).

In one or more embodiments, first display 18 comprises arectangle-shaped display (e.g., LCD, plasma, OLED, QLED, etc.) with acircular cutout in housing 15 in front of first display 18, thus makingit appear circular. Alternatively, it is also considered that firstdisplay 18 is a circular display.

Different background colors 22 are used to indicate to users at adistance if level 10 is perfectly or closely aligned with the target.For example, when reading line 20 and target 24 are aligned and/ornearly aligned, background 22 may be a color that is easy to recognizefrom a distance, such as green, which indicates that the level isperfectly or nearly perfectly aligned with the target. When reading line20 and set target 24 are not aligned, but reading line 20 is withinacceptable margin 26, background 22 may be yellow, which indicates thatthe level's orientation is within the acceptable range, although notperfectly aligned. When reading line 20 is outside the markings ofacceptable margin 26, background 22 may be black and the lettering iswhite, which indicates that the orientation of level 10 is notacceptable, and thus the underlying structure that level 10 is disposedagainst should be adjusted.

Battery status 32 is used to communicate the remaining amount of chargein power supply module 14 (e.g., a battery). Power supply module 14 mayinclude one or more batteries, which are arranged within housing 15.

Turning to FIG. 3, in another embodiment and/or configuration, ratherthan using acceptable margin markings 26, target ranges are used. Whenreading line 20 is within primary target range 36, then background 22may be a first color (e.g., green) to indicate that the currentorientation is acceptable. When reading line 20 is outside primarytarget range 36 but within secondary target range 38, background 22 maybe a second color (e.g., yellow) to indicate that the current is closebut not perfect, and thus may be acceptable for some less-demandingsituations (e.g., a wooden support beam with an uneven surface may onlyneed to be “mostly” level, in part because the uneven surface makes itdifficult to determine a precise orientation). When reading line 20 isoutside secondary target range 38, background 22 may be a third color(e.g., black) while the numbers and features are in white.

In one embodiment, secondary target range 38 is a fixed number ofdegrees broader than primary target range 36 (e.g., 0.5 degrees broaderin both directions, 1 degree broader in both directions, 5 degreesbroader in both directions, 10 degrees broader in both directions). Inanother embodiment, secondary target range 38 is a relative amountbroader than primary target range 36 (e.g., 25% broader in bothdirections, 50% broader in both directions, 100% broader in bothdirections, 200% broader in both directions).

In another embodiment, primary target range 36 is non-symmetrical withrespect to the target reading (e.g., 1 degree in one direction and 0.5degrees in the other direction). Similarly, it is also contemplated thatsecondary target range 38 is non-symmetrical.

In one or more embodiments, several visual features, such as elements 78in first display 18, rotate within first display 18 to maintain ahorizontal orientation with respect to the ground. For example, even ifhousing 15 of level 10 is at a 45 degree angle with respect to theground, then several elements 78 in first display 18, such as reading28, battery status 32, reading line 20, and history 30, are horizontalwith respect to the ground. Therefore, in this example reading 28,battery status 32, reading line 20, and history 30 would be displayed ata 45 degree angle with respect to housing 15. However, because theseelements 78 are horizontal with respect to the ground, they are easierfor a user to read.

While the one or more features rotate around first display 18, firstdisplay 18 does not itself rotate physically. Instead, graphic featuresare displayed on first display 18 in a manner that provides theappearance of physical rotation.

History 30 displays a recent measurement recorded by level 10. Forexample, in FIG. 2 history 30 displays “3.1”, to indicate that theprevious recorded orientation of level was at that angle. A measurementmay be recorded by level by any of several methods, including pressing acertain input button on level 10, or leaving level 10 in a certainorientation for a threshold length of time. By interacting with inputmodule 50, described below, a user may store any of several historicalmeasurements, and display one or more of those historical measurementsat history 30.

Turning now to FIGS. 4-6, display 18 operates in a coarse view mode whenlevel 10 is outside of a view mode threshold of target 24, such as 3degrees (best shown FIG. 5). When level 10 is within the view modethreshold of target 24, display 18 operates with a more detailed view(best shown FIG. 4). For example, when the orientation of level 10(e.g., which may be represented by reading line 20) is more than 3degrees away from target 24, display 18 displays coarse outer ring 114(e.g., FIG. 5), and when the orientation of level 10 is within 3 degreesof target 24, display 18 transitions to displaying fine outer ring 116(e.g., FIG. 4). In this example, level 10 having an orientation of 3degrees away from target 24 refers to 1.5 degrees in either direction.

Continuing to refer to FIG. 4, detailed primary range 120 surroundstarget 24 over 0.5 degrees of arc in either direction with respect totarget 24. Detailed secondary range 122 adds another 1.0 degree ofchange in orientation beyond detailed primary range 120 to either endaway from target 24. The combination of detailed primary range 120 anddetailed secondary range 122 includes a total range of 1.5 degrees ineither direction. However, although detailed primary range 120 anddetailed secondary range 122 combined correspond to 1.5 degrees ofchanged orientation for level 10, detailed primary range 120 anddetailed secondary range 122 visually extends approximately 30 degreesof circumferential arc around display 18 (best shown in FIG. 4) toeither direction from target 24. Therefore, movement of reading line 20within image 76 is an exaggerated representation of orientation changesto level 10. For example in this embodiment a single degree of change tothe orientation of level 10 corresponds to reading line 20 transitingthrough 20 degrees of circumferential distance across detailed primaryrange 120 and/or detailed secondary range 122. This exaggerated movementof reading line 20 in image 76 as compared to the physical orientationchange of level 10 assists the user in more easily making fine-tuneadjustments to align a surface with a target orientation.

For illustrative example, when the orientation of level 10 is 1.5degrees from target 24, reading line 20 is at reference point A in FIG.4 with a 30 degree angle from target 24 in display 18 and aligned withan end of detailed secondary range 122 that is furthest from target 24.When the orientation of level 10 changes 0.5 degrees towards target 24,and is therefore 1.0 degrees from target 24, reading line 20correspondingly circumferentially moves to reference point B in FIG. 4halfway through detailed secondary range 122 toward detailed primaryrange 120. When the orientation of level 10 changes yet another 0.5degrees towards target 24, and is therefore 0.5 degrees from target 24,reading line 20 correspondingly moves the rest of the way throughdetailed secondary range 122 to reference point C in FIG. 4, arriving atthe intersection between detailed primary range 120 and detailedsecondary range 122. When the orientation of level 10 changes still yetanother 0.5 degrees towards target 24, and is therefore aligned with thetarget 24, reading line 20 correspondingly aligns with target 24 atreference point D in FIG. 4. In this example, even though theorientation of the physical level 10 itself only changed by 1.5 degreesin the physical world, the position of reading line 20 moved 30 degreesacross fine outer ring 116.

In this example one degree of change to level's 10 orientationcorresponds to 20 degrees of movement of reading line 20 around fineouter ring 116 (a ratio of 1:20:change of the orientation of level 10:circumferential movement of reading line 20 in display 18). In variousother embodiments, other ratios are practiced (e.g., one: three or more,one: five or more, one: ten or more, and/or one: thirty or more).

During use of level 10, directional indicator 124 transits the innercircumference of outer ring 112 in a circular rotation, such that darkedge 126 leads the front edge of directional indicator 124, and lightedge 128 trails directional indicator 124. In one embodiment directionalindicator 124 is very dark (e.g., high contrast to the background color)at dark edge 126 and directional indicator 124 slowly transitions tobeing relatively light (e.g., low to no contrast to the backgroundcolor) at light edge 128. Directional indicator 124 transits the innercircumference of fine outer ring 116 in circumferential direction 100.In various embodiments, two directional indicators 124 circumferentiallyrotate around the inner circumference of fine outer ring 116 on oppositesides of fine outer ring 116. The speed of directional indicators 124corresponds to the difference between target 24 and reading line 20,such that the further the orientation of level 10 is from the desiredtarget, the faster directional indicator 124 rotates. The rotationaldirection of directional indicator 124 corresponds to the direction thatlevel 10 needs to rotate to the targeted orientation. The rotationalspeed of directional indicator 124 corresponds to how close level 10 isto the target orientation (e.g., directional indicator 124 moves slowerwhen the orientation of level 10 is within detailed primary range 120than within detailed secondary range 122).

Turning to FIG. 6, illustrated therein is a graphical representation ofthe ranges that primary range 120 and secondary range 122 correspond toin an exemplary display 18. For example, primary range 120 coversapproximately 20 degrees of arc in display 18 even though primary range120 actually corresponds to 2 degrees of rotation of level 10, andsecondary range 122 covers approximately 45 degrees of arc in display 18even though secondary range 122 corresponds to 4.5 degrees of rotationof level. As indicated in FIG. 6, in one embodiment detailed primaryrange 120 extends the same circumferential distance in either directionfrom target 24. Detailed secondary range 122 similarly extends the samecircumferential distance in either direction from each of acceptablemargins 26.

In various embodiments the orientational precision of level 10 requiredto minimally satisfy the requirements of detailed primary range 120 anddetailed secondary range 122 is selectable by a user. For example, inthe embodiment(s) of FIGS. 4-6 the orientation of level 10 can be up to0.5 degrees from the target orientation and satisfy the requirements ofdetailed primary range 120, or be between 0.5 degrees and 1.5 degreesfrom the target orientation and satisfy the requirements of detailedsecondary range 122. In various other embodiments detailed primary range120 is configured to correspond to no more than X degrees of orientationaccuracy of level 10 (e.g., 0.1 degrees, 0.05 degrees). The adjustmentsto the accuracy requirements can be input to level 10, for example, viainput module 50.

Turning to FIGS. 7-10, display 18 is in a coarse view because level 10is not sufficiently close to the target orientation. Specifically, level10 is oriented at an angle of thirty degrees with respect to levelground. As a result, reading 28 indicates a reading of “30.00” degreesand reading lines 20 are oriented at a corresponding thirty degree angleaway from target 24.

Background 22 of display 18 changes color when level 10 is orientedwithin detailed primary range 120 of target 24. In one or moreembodiments, target 24 is manually set to a target reading. For example,the targeted orientation of level 10 may be set by placing level 10 atthe target orientation and pressing mark button 56. Alternatively, level10 may be placed near the target orientation (e.g., the targetorientation is 30 degrees, and level 10 is placed at 28.5 degrees), markbutton 56 is depressed to set 28.5 as a temporary target, and inputbuttons 52 are used to manually adjust the target from 28.5 degrees to30 degrees. As yet another alternative, the target orientation of level10 may be manually set solely by use of input buttons 52.

In various embodiments, in situations in which the target orientation isother than level or plumb (e.g., if the target is 30 degrees), display18 continues to display a non-zero reading 28 even when level 10 isoriented consistent with the target. Reading 28 displays the measuredorientation of level 10 with respect to level ground, rather thandisplaying a difference between reading line 20 and target 24. In otherembodiments reading 28 specifies the difference between reading line 20and target 24. As level 10 approaches the targeted orientation, reading28 increasingly approaches zero until reading 28 is at or near zero evenwhen the target orientation is not itself zero.

In the absence of a manually set target, target 24 is a default targetsuch as one of level with level ground (e.g., a reading of 0 degrees) ortarget 24 is plumb to level ground (e.g., a reading of 90 degrees). Asshown in FIG. 10, when level 10 is aligned with plumb 23 of levelground, and therefore within detailed primary range 120, background 22changes to a first color (e.g., green). When level 10 is aligned withdetailed secondary range 122 of target 24, background 22 changes to asecond color (e.g., blue). In one embodiment level 10 changes target 24from level ground to plumb depending on which is closer to theorientation of level 10.

By default, level 10 is configured to have target measurements of 0degrees (parallel to level ground, or to put it another wayperpendicular to the perceived force of gravity) or 90 degree(perpendicular to level ground, or to put it another way parallel to theperceived force of gravity). Accordingly, when level 10 has anorientation that approaches and/or equals one of those measurements,background 22 of display 18 may change color to indicate that theorientation is close and/or correct. To toggle the ability to configurecustom-identified orientation targets, mark button 56 may be quicklypressed to enable/disable this functionality (e.g., turning Mark Mode onand off). When level 10 is positioned at a target orientation, markbutton 56 may be held for a short period of time (e.g., two seconds) toindicate that this is the target orientation for level.

Turning to FIGS. 11-12, level 10 further includes the ability to flip,or mirror-image, the target orientation of level 10 with respect to theperceived force of gravity. This can be useful if a measuring surfacerequires level 10 to face a different direction so that display 18 isnot visible. Level 10 can be reconfigured so that the mirror-image of atarget orientation is the desired target for the next measurement (e.g.,in FIG. 12 target 24 is aligned with reading line 20 when the right-sideof level 10 is 18.5 degrees above parallel to level ground 21). Thisflipping of the target mark for level 10 can be accomplished, forexample, by double-tapping mark button 56. For example, if the targetorientation is the left-side of the level being 13 degrees higher thanthe right-side of the level, the mirror-image target orientation is theright-side of the level being 13 degrees higher than the left-side ofthe level.

Turning to FIG. 13-15, list 31 is displayed on display 18 and includesseveral (e.g, three) orientation measurements that can be selected. Thisallows users to quickly toggle between commonly occurring targetorientations. The entries in list 31 can be selected by a user to settarget 24 for level 10. For example, the first entry in list 31 is 7.56degrees, the second entry in list 31 is 8.5 degrees, and the third entryin list 31 is 12.5 degrees. In response to a user selecting the secondentry (best shown in FIG. 15), target 24 for level 10 becomes 8.5degrees different than level ground. In various embodiments entries inlist 31 is input to level 10, such as via input module 50. Entries inlist 31 can be adjusted, added, and/or removed by a user.

Referring to FIG. 16, controller 12 is in electrical communication withaccelerometer module 60, input module 50, and display module 16.Controller 12 also controls power supply module 14, with a goal ofminimizing energy expenditures from the battery or batteries. It isconsidered that controller 12 may be implemented via hardware, such as amicroprocessor (e.g., an ASIC), software, firmware, and/or anycombination thereof.

In one or more embodiments controller 12 calculates the orientationdifference of level 10, determines which mode to operate in, determineswhich image(s), if any, to display on the one or more displays, andsends control signal(s) to the display to emit an image indicating theorientation difference. Controller 12 may utilize several modes, such asan active mode, a sleep mode, and a disabled functionality mode. Thesleep mode and the disabled functionality mode are utilized to preservebattery power. In active mode, all of the features are enabled, and thedisplay is fully lit (e.g., not dimmed). In disabled functionality mode,which may be activated when battery power is below a threshold,controller 12 may reduce power supply to any of several features, suchas one or more displays may be dimmer, one of the displays may beentirely turned off, the level may enter sleep mode after a thresholdperiod of time that is shorter than during normal operations, only oneof the accelerometers may be utilized, etc.

Further, the disabled functionality mode may prioritizeelectronic/powered features within the level when the battery level islow. For example, such a method may disable certain features, such aslighting features (e.g., the background color) or sound features (e.g.,notifications that the orientation is within one of the ranges), inorder to maintain sufficient power for other features. Such basicfeatures may include the position/level sensors and the digital displayof level/position information on a digital level display.

Controller 12 may enter a sleep mode, which disables all features oflevel 10 except the power button 54 and the ability to charge thebattery/batteries. Sleep mode may be entered because any of severaltriggers are detected, such as if the power button is engaged to togglelevel 10 off, if there is no user input for a threshold period of time,if there is no movement for a threshold period of time, if there is toomuch movement for a threshold period of time (e.g., if level 10 is beingcarried during a lengthy walk), etc.

Turning back to FIG. 16, controller 12 has several features andconfigurations to preserve battery power. One aspect of the power savingfeatures is based on level 10 including at least two processors. In theembodiment schematically illustrated in FIG. 16, level 10 includes firstCPU 82 and second CPU 84. First CPU 82 utilizes more power than secondCPU 84. For example, first CPU 82 may operate at a faster clock speed,it may be a physically larger processor, it may measure orientation oflevel to a greater level of accuracy (e.g., to hundredths of degrees(e.g., 18.23 degrees) as opposed to whole degrees (e.g., 18 degrees)),it may have increased functionality, etc. In various embodimentsprocessors other than a CPU may be utilized, including withoutlimitation, an MCU, an MPU, and/or an ASIC.

As a result, it behooves controller 12 to selectively disable and/orreduce the power draw by first CPU 82 to provide support for theoperation of level 10. While first CPU 82 is disabled and/or has areduced functionality, in various embodiments controller 12 relies onsecond CPU 84 to monitor operations of level 10 and to determine whetherand when to activate first CPU 82.

Controller 12 operates using several modes. One mode is the “Off Mode”,in which most or all components of level 10 are disabled with theexception of power button 54. Another mode is the “On Mode”, in which atleast first CPU 82 is operational, and thus at least a majority offeatures of level 10 are operational.

Another mode is a “Sleep Mode”, in which level 10 is powered on but hasreduced functionality. For example, when level 10 has not been moved fora period of time (e.g., 2 minutes), as a result of that stasis,controller 12 places level 10 in Sleep Mode, in which first CPU 82 isdisabled and/or has reduced functionality and second CPU 84 is enabledand utilized by controller 12. In another example, when level 10 isplaced with an unusable orientation (e.g., if front display 18 is facingtowards the ground, such as if level 10 is placed face-down on a tableor workpiece, or if front display 18 is placed face-up), controller 12may place level 10 in Sleep Mode.

Another mode is “Power Save Mode”, in which level 10 is still active buthas a reduced functionality. For example, in this mode at least one offirst display 18 or second display 40 may be disabled and/or havepartial functioning (e.g., display 18 or 40 may be dimmed). As anotherexample, in this mode first CPU 82 may be disabled, and as a resultlevel 10 has a reduced accuracy of orientation measurements (e.g., theorientation of level 10 can only be determined to a whole degree ofaccuracy (e.g., 18 degrees), rather than a more precise measurement,such as to tenths of degrees (e.g., 18.1 degrees) or hundredths ofdegrees (e.g., 18.23 degrees)).

Level 10 may be manually placed in Power Save Mode by a user selectingthis mode via input module 50. Alternatively, level 10 may be placed inPower Save Mode as a result of a reduced power supply that is availableto level 10.

Another mode is “Depleted Mode”, in which level 10 has a restrictedfunctionality. Level 10 enters this mode when the power supply availableis below a certain threshold (e.g., 10 percent, 20 percent). In DepletedMode, similar to Power Save Mode, at least one of first display 18 orsecond display 40 may be disabled and/or have partial functioning (e.g.,display 18 or 40 may be dimmed). For example, in Depleted Mode firstdisplay 18, which may consume more power than second display 40, isdisabled.

Turning now to FIG. 17, in various embodiments input module 50 comprises“Menu/select” button 52, labeled “ . . . ”, that allows the user to opena menu for level 10. The user cycles through menu options by continuingto press the “ . . . ” button 52, or the user cycles through menuoptions by pressing the up or down arrow buttons 52.

Input module includes comprises input buttons 52, a power button 54, anda mark button 56. Mark button 56 allows a user to “mark” an orientationof the level on a selected surface as the target orientation for futuresurfaces. For example, if a cross beam is oriented at a certain anglewith respect to the ground (e.g., 2 degrees), level 10 can be placed onthe target support beam. Mark button 56 is then used to indicate tocontroller 12 in level 10 that the angle of the target support beamshould be memorized and duplicated in future readings. Alternatively, atarget angle for level 10 may be set by the user via input buttons 52.

The input buttons may be used to adjust various settings of level 10,including language settings (e.g., what language to use), adjusting thevarious ranges (e.g., primary target range 36, secondary target range38, detailed primary range 120, and/or detailed secondary range 122),adjusting the default thresholds to enter sleep and/or disabledfunctionality modes (both discussed further below), and notifications(e.g., which background colors indicate which orientations).

FIGS. 18-19 illustrate an exemplary accelerometer module 60 in level 10.In this embodiment, bottom 64 of first accelerometer 62 is on the topleft, bottom 74 of second accelerometer 72 is on the bottom left, andbottom 68 of accelerometer module 60 is on the left, from theperspective of FIG. 18. Bottom 68 of accelerometer module 60 isgenerally coplanar with measuring surface 8 of level 10. Thus, firstaccelerometer 62 has a first angular position relative to measuringsurfaces (e.g., 6 and 8) of level 10 and second accelerometer 72 has adifferent second angular position relative to measuring surfaces (e.g.,6 and 8) of level 10. In this embodiment, first accelerometer 62 isoriented at a +45 degree (positive forty-five degree) angle with respectto measuring surface 8 on the bottom of level 10 and also relative toaccelerometer housing 66. The positive aspect of this angle indicatesthat the rotation is clockwise with respect to the selected viewingperspective, which in this example is illustrated in FIG. 18. Thus, inthis embodiment first accelerometer 62 is oriented at a −45 degree angleto housing 15. Based on the position of bottom 74 of secondaccelerometer 72, it can be seen that second accelerometer 72 isoriented at a −45 degree (negative forty-five degree) angle with respectto measuring surface 8 on the bottom of level 10 and also relative toaccelerometer housing 66. The negative aspect of this angle indicatesthat the rotation is counter-clockwise with respect to the selectedviewing perspective, which in this example is illustrated in FIG. 18.

Therefore, in this embodiment first accelerometer 62 has a first angularposition relative to a first measuring surface of level 10, and secondaccelerometer 72 has a different second angular position relative tofirst measuring surface of level. First accelerometer 62 and secondaccelerometer 72 are oriented at a 90 degree angle with respect to eachother. This complimentary orientation of first and second accelerometersprovides a more precise measurement at the orientations that are mosttypical, i.e., 0 degrees, 90 degrees, 180 degrees, and 270 degrees. Themargin of error at those angles may be at or approach zero (see FIG.19), while the maximum margin of error at other angles (i.e., 45degrees, 135 degrees, 225 degrees, 315 degrees) still remains small. Inanother embodiment first accelerometer 62 and second accelerometer 72are rotationally oriented relative to each other so that they havedifferent orientations with respect to the housing (e.g., oneaccelerometer is 30 degrees off level compared to the housing and theother accelerometer is 60 degrees off level compared to the housing).

As is illustrated in FIG. 19, in the orientation described andillustrated in FIG. 18, first accelerometer 62 has its most precisemeasurements at 90 degrees and 270, while second accelerometer 72 hasits most precise measurements at 0 degrees and 180 degrees and 360degrees (which is equivalent to 0 degrees).

In one or more embodiments, where the measurements of the twoaccelerometers is unequal, only the measurement from the more preciseaccelerometer is used and communicated to the user. However, it iscontemplated that the two measurements could be combined to generateoutput for the user (e.g., an average of the two measurements, aweighted average whereby the more precise accelerometer measurement,such as according to the chart in FIG. 19, is given a greater weight).

In one or more embodiments level 10 does not include vials with liquidand an air bubble, although in an alternative embodiment digital level10 may also include such vials, such as is shown in FIG. 20. Vials maybe oriented in complimenting orientations, such as perpendicular andaligned with longitudinal axis 4 of housing 15.

Further, in one or more embodiments level 10 includes second display 40,which is disposed on a top surface of housing 15. Second display 40communicates a number representing the angle of level 10, a numberrepresenting the target angle, and optionally a symbol that indicateswhich side of level 10 may be too high or low. However, it iscontemplated that second display 40 includes some or all of thegraphical elements in first display 18.

As referenced throughout, the term level ground refers to ground that isgenerally coplanar to the plane perpendicular to the perceived force ofgravity.

It should be understood that the figures illustrate the exemplaryembodiments in detail, and it should be understood that the presentapplication is not limited to the details or methodology set forth inthe description or illustrated in the figures. It should also beunderstood that the terminology is for description purposes only andshould not be regarded as limiting.

Further modifications and alternative embodiments of various aspects ofthe invention will be apparent to those skilled in the art in view ofthis description. Accordingly, this description is to be construed asillustrative only. The construction and arrangements, shown in thevarious exemplary embodiments, are illustrative only. Although only afew embodiments have been described in detail in this disclosure, manymodifications are possible (e.g., variations in sizes, dimensions,structures, shapes and proportions of the various elements, values ofparameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter described herein. Someelements shown as integrally formed may be constructed of multiple partsor elements, the position of elements may be reversed or otherwisevaried, and the nature or number of discrete elements or positions maybe altered or varied. The order or sequence of any process, logicalalgorithm, or method steps may be varied or re-sequenced according toalternative embodiments. Other substitutions, modifications, changes andomissions may also be made in the design, operating conditions andarrangement of the various exemplary embodiments without departing fromthe scope of the present invention.

Unless otherwise expressly stated, it is in no way intended that anymethod set forth herein be construed as requiring that its steps beperformed in a specific order. Accordingly, where a method claim doesnot actually recite an order to be followed by its steps or it is nototherwise specifically stated in the claims or descriptions that thesteps are to be limited to a specific order, it is in no way intendedthat any particular order be inferred. In addition, as used herein, thearticle “a” is intended to include one or more component or element, andis not intended to be construed as meaning only one. As used herein,“rigidly coupled” refers to two components being coupled in a mannersuch that the components move together in a fixed positionalrelationship when acted upon by a force.

Various embodiments of the invention relate to any combination of any ofthe features, and any such combination of features may be claimed inthis or future applications. Any of the features, elements or componentsof any of the exemplary embodiments discussed above may be utilizedalone or in combination with any of the features, elements or componentsof any of the other embodiments discussed above.

We claim:
 1. A level comprising: a housing comprising a longitudinal axis; a planar base surface; a top surface opposing the base surface; an orientation sensor configured to measure an orientation of the housing with respect to a perceived direction of the force of gravity; a controller that calculates an orientation difference between the housing orientation and a target orientation; and a display that emits an image that corresponds to the orientation difference, the display rotating the image in response to a rotation of the housing so that the image maintains a consistent orientation with respect to the perceived direction of the force of gravity.
 2. The level of claim 1, the orientation sensor comprising at least two accelerometers rotationally oriented relative to each other such that the two accelerometers have different orientations with respect to the housing.
 3. The level of claim 1, the orientation sensor comprising first and second accelerometers, the first accelerometer comprising an orientation that is rotated 90 degrees compared to an orientation of the second accelerometer.
 4. The level of claim 1, wherein the image comprises alphanumeric characters that are indicative of the housing orientation.
 5. The level of claim 1, the image comprises a level mark that indicates a plane perpendicular to the force of gravity, and a plumb mark that indicates a plane parallel to the force of gravity.
 6. The level of claim 1, wherein the level receives input to adjust the target orientation based on a current orientation of the housing.
 7. The level of claim 6, wherein the level receives input to adjust the target orientation to the current orientation of the housing.
 8. The level of claim 1, wherein the image comprises a first image and the display emits a second image that does not rotate in response to rotation of the housing.
 9. The level of claim 1, wherein the controller transmits a control signal to the display, and the image emitted by the display is based on the control signal.
 10. A level comprising: a housing with a longitudinal axis; a planar base surface; a top surface opposing the base surface; an orientation sensor to measure an orientation of the housing with respect to a perceived direction of the force of gravity; a controller that calculates an orientation difference between the housing orientation and a target orientation; and a display that emits an image that corresponds to the orientation difference, the display adjusting the image from a first image to a second image as a result of a determination that the orientation difference is less than a first threshold.
 11. The level of claim 10, wherein the image comprises an exaggerated representation of the housing orientation.
 12. The level of claim 11, the exaggerated representation in the image comprising a first angle that is at least three times the orientation difference.
 13. The level of claim 11, the exaggerated representation in the image comprising a first angle, the display adjusting the first angle in the exaggerated representation by X degrees of arcuate movement as a result of the housing orientation being rotated by Y degrees, wherein X>Y.
 14. The level of claim 11, the exaggerated representation in the image comprising a first angle, the display adjusting the first angle in the exaggerated representation by X degrees of arcuate movement as a result of the housing orientation being rotated by Y degrees, wherein X is at least five times Y.
 15. The level of claim 11, the exaggerated representation in the image comprising a first angle, the display adjusting the first angle in the exaggerated representation by X degrees of arcuate movement as a result of the housing orientation being rotated by Y degrees, wherein X is at least ten times Y.
 16. The level of claim 11, the exaggerated representation in the image comprising a first angle, the display adjusting the first angle in the exaggerated representation by X degrees of arcuate movement as a result of the housing orientation being rotated by Y degrees, wherein X is at least thirty times Y.
 17. The level of claim 10, the image comprising a first background color as a result of the housing orientation being within a first range of the target orientation, and the image comprising a second background color as a result of the housing orientation being within a second range of the target orientation.
 18. The level of claim 17, wherein the level receives input to adjust at least one of the first range and the second range.
 19. The level of claim 10, wherein the level receives input to set the target orientation based on a current orientation of the housing.
 20. The level of claim 19, wherein the level receives input to adjust the target orientation to its mirror-image with respect to the perceived force of gravity.
 21. The level of claim 10, the displayed image comprising a plurality of user-selectable target orientations.
 22. The level of claim 21, the level receives an input to adjust an entry in the plurality of user-selectable target orientations.
 23. A method of controlling a level comprising: placing a level against an object surface, the level comprising: a housing with a longitudinal axis; a planar base surface; a top surface opposing the base surface; an orientation sensor; a controller; and a display; the orientation sensor measuring an orientation of the housing with respect to a perceived direction of the force of gravity; the controller calculating an orientation difference between the housing orientation and a target orientation; the display emitting an image indicating the orientation difference; the controller determining to enter the Sleep Mode; and in response to the controller determining to enter the Sleep Mode, the display stops emitting the image indicating the orientation difference.
 24. The method of claim 23, the controller determining to enter the Sleep Mode as a result of being immobile for a time period.
 25. The method of claim 23, the controller determining to enter the Sleep Mode as a result of the housing being placed in a predetermined orientation.
 26. The method of claim 23, the plurality of power modes further comprising a Depleted Mode that the controller enters when a power source for the level is below a predetermined level. 